Nightmare scenario here...with a number of 5x7 negative sleeves having been evidently peed on by a mouse, with the sleeves then having wicked some of this pee in to "infect" about a dozen or so images, about half of which are "keepers."

So what I've done so far is to very carefully cut the sleeves apart and discard them, then run the infected negatives through a series of four trays...two of plain water and two with Photo-Flo - in nitrile-gloved hands and very gently rubbing the areas affected.

The cleaned up negatives, when viewed in oblique light, do show a bit of difference in the affected areas - but this is very subtle. When viewed on a lightbox, I can see absolutely nothing indicating that they'd been affected.

Question: my guess is that our slightly alkaline deep-well water would tend to help neutralize what must have been some rather acidic pee...but have I gone far enough? Should I run these negatives through a tray of (alkaline) TF-5 fixing bath, then rewash them?